This study is designed to evaluate the: 1) Effect of purified pancreatic enzymes (amylase, lipase, phospholipase A and trypsin) on the ultrastructure of the rabbit gallbladder and upon the major constituents of bile, after 24 hours, 4 weeks and 8 weeks, when these enzymes have been injected into the gallbladder as sterile solutions. 2) Effect which pancreatic enzymes and inflammatory changes in the gallbladder wall have upon the active transport of Na ion, Cl minus and H2O, and upon its selective permeability. 3) Relation of alterations of function to changes in micellar stability of bile and the solubilization of cholesterol. 4) The changes which occur in bile following incubation with specific pancreatic enzymes.